4-Fluorophenethylamine and other fluorine-containing substituted phenethylamines are interesting intermediates, for example for preparing agrochemicals. J. Am. Chem. Soc. 63, 602 (1941) discloses that 4-fluorophenethylamines can be prepared in a multi-step process. Here, p-fluorophenethyl alcohol is obtained starting from p-fluorophenylmagnesium bromide by addition to ethylene oxide with subsequent hydrolysis and converted with phosphorus tribromide into p-fluorophenylethyl bromide which is hydrolyzed with ammonia to give the target product. Disadvantages of using this process, especially on a relatively large scale, are, in addition to the large number of steps involved, the technical expense required for carrying out a Grignard reaction, including the required safety measures, and the use of phosphorus tribromide which is costly and the handling of which likewise requires high expenditure for safety measures. Alternatively, according to J. Org. Chem. 23, 1979 (1958), it is also possible to use p-fluorobenzyl chloride as starting material, which is reacted with sodium cyanide to give p-fluorophenylacetonitrile which is then reduced using sodium alanate. If this route was to be realized on an industrial scale, the use of the highly toxic sodium cyanide would require particular safety measures. The use of sodium alanate, which is known to react explosively with halogenated hydrocarbons (see Rompp Lexikon Chemie Version 1.3 on CD-ROM (1997)), renders this process completely useless for industrial application.
N-[2-(Fluorophenyl)-ethenyl]-phthalimide is disclosed in J. Org. Chem. 58, 3299 (1993). In this publication, it is described as being obtainable from an iodine compound. This process is uneconomical. It was contrary to expectations that this and other fluorine-containing .beta.-iminovinylbenzenes could be obtainable in a simple manner.